A Beginner’s Guide to G-Code in 3D Printing

What is G code in 3D Printing scaled


Table of Contents

3D printing involves many technical steps, such as designing the object and the additive manufacturing processes for accurate model printing. However, all these technical steps are useful only if you use well-created G-code.

The particular reason for creating and using the G-code command is that it enables the printer to print high-quality 3D models onto the print bed through its additive manufacturing process. Another amazing thing about G-code is that it is easy to create/program since it is a simple set of instructions that the 3D printer needs for successful 3D printing.

Whether you are a beginner or an expert at creating and using G-code, this article has something for you. If you keep reading this post, you will learn how to program a G-code for your 3D design, how to write it, its benefits, and the best software to use for creating G-code.

What is G-Code in 3D Printing?

G-code is a CNC (computer numerical control) program language that can automatically instruct the 3D printer, specifically the print head and extruder, on when to move, how to extrude, and other 3D printer functions that require a change in position.

Firstly, the 3D printers translate and decode the G-code commands -this takes only a short time- then the G-code can automatically start controlling the 3D printer’s printing movement.

Meaning the 3D printer uses the G-code instructions to move and convert the heated filament in the extruder into real-life, physical objects called 3D models or 3D model objects. When this happens, it becomes a computer-aided manufacturing process that, in turn, prints a high-quality 3D model.

Some other underground processes that could occur during 3D printing with G-codes are:

  • Bed leveling with the aid of an adhesion assistant.
  • CNC milling is a subtractive manufacturing process belonging to the G-code instructions.
  • Collaborating with additional parameters from the 3D printing machine to construct models

Lastly, you should know that the G-code is crucial to any 3D printing process. It gives users precise control over the print head movement when using complex bed leveling systems to print the base of the adhesion assistant.

How to Create G-Code for 3D Printing

Before starting any 3D printing project, it is vital to have a basic understanding of G-code. You should understand what you want it to do, how it can help your 3D printing process, how to create a custom G-code command, and more.

Besides empowering 3D printing businesses and engineers to effortlessly 3D print, it helps users notice potential issues during the 3D print process. It is a straightforward process, so don’t worry.

With the information in this post and the right mindset, you can maximize the full potential of G-coded 3D printing!

The first step in creating your custom G-code is to find a 3D modeling program that allows you to design the model you would like to construct on the print bed. Fortunately, many slicers, such as SketchUp and Blender, are free online.

Once you have the 3D model of your choice ready to go, it’s time to start creating the 3D printer G-code.

Luckily, some of the most popular CNC-programmed software, such as G-Wizard Editor, will allow you to edit, create, and simulate G-codes for a longer-lasting tool life for your 3D printer.

You can also create this program using the 3D printer’s G-code normal mode in its default settings.

Once you have inputted the G-code’s coordinate parameters into the normal mode of the 3D printer, the 3D printer is ready to follow the G-code instructions. Plus, you can adjust the settings within the normal mode to control the extruder temperature aside from controlling the printer head movement around the print bed.

The next step is fixing it to your 3D printer using an external storage device. After transferring the G-code into storage supports such as a USB or SD card, insert it into a 3D printer for testing or use a simulator to test the G-code for errors.

Examples of G-Codes for 3D Printing

Knowing some G-code commands will make it easier for you to start the main 3D printing process (i.e., the printing itself). In this part of the post, we will share just 9 simple and common commands you will use most of the time. Understanding how they work can help you get the best 3D prints every time.

With a little practice, 3D printing with G-code can become as easy as pushing a button. Here are some examples of common G-code languages in commands:

Rapid Linear Move Command

The first type of G-code is called “G0” or “rapid linear move command.” This G-code command is similar to but differs from G1 because it is a rapid move command that instructs the 3D printer to move quickly and change its current position.

For example, G0 X10 Y20 Z30 would tell the 3D printer to move 10 mm in the X direction, 20 mm in the Y direction, and 30 mm in the Z direction at a fast speed.

Support Command

The second type of G-code is called “G2” or “support commands.” These instructions tell your 3D printer to generate support structures during the model’s construction time. For example, G2 E0.15 F150 would tell the 3D printer head to extrude 0.15 mm of material at 150 mm/min to create a support structure for a 3D model.

Print Command

The third type of G-code is called “G1” or “print commands.” These instructions tell your 3D printer to start printing a 3D model by moving the nozzle/extruder to a preset location on the print bed. For example, G1 X10 Y10 E0.25 F300 would tell the 3D printer to move to location 10 on the print bed and extrude 0.25mm of material at that location at 300 mm/min.

Laser Engraving Command

Another type is the G-code for laser engraving or cutting in 3D printing. It differs for each 3D printer. But don’t worry; with this Laser mode 3D printing article and your 3D printer’s manual, you will do just fine.

Absolute Mode Command

The fifth example of the G-code command we will share in this post is “G90” or “Absolute Mode,” which can help your printing machine construct quality models onto the print bed. This G90 or Absolute Mode instructs your 3D printer to change its current position completely.

For example, G90 G0 Z15 would tell the print head to move to an absolute position of Z15.

Homing Command

The sixth example of G-code commonly used is “G28” or “homing command.” This command refers to the movement of the print head to the first starting position for printing the model. G28 instructs the print head to move to the starting position, usually the corner of the model.

Temperature Command

The seventh example of a G-code command is the “M104 command” or “nozzle temperature command.” This G-code starts with M because it is an M-code, so it does not fit into other G-code categories since it specifically sets the target temperature of the extruder.

The nozzle temperature command informs the nozzle when it is time to extrude by controlling the target temperature with an additional parameter called the S parameter. Note that the S parameter measures the temperature in degrees Celsius.

However, this M104 command does not wait for the nozzle/extruder to reach the target temperature before beginning the printing process. This is why many use M109, i.e., to permit proper heating. M104 S200, for example, allows the melting and extrusion of the filament for the actual model construction when the target temperature of 200 is reached.

Fan Speed Command

The eighth example is “M106” or “fan speed command.” This command instructs the printer’s cooling fan to switch on and designates the specific speed at which the fan should oscillate with the S parameter.

However, the S parameter here specifies the pulse width modulation of the fan and controls the fan.

The letter M in M106 stands for miscellaneous command and means it does not belong to the other categories of G-code, similar to all M G-code commands. Putting this together, a good example is M106 S128 which will turn on the cooling fan and set the fan speed at 50 percent.

Emergency Stop G-Code Command

This is the ninth G-code example. Users refer to it as the “M112 command” or “emergency stop G-code command” and use it to stop the functioning of the 3D printer machine regardless of previous commands during the 3D print job time.

M112 works by immediately terminating the printer machine’s job and completely canceling the current print job. For example, M112 between other G-code commands will trigger an emergency termination of the print job timer and printer’s operation.

The Wipe Nozzle Command

The wipe nozzle command is the last example of the G-code command we will share in this post.

Unlike the other examples mentioned above, the wipe nozzle command does not have a specific number. Instead, it uses the following command queue to clean the nozzle successfully:

  • G1 command to change the current position of the nozzle/print head.
  • Then the E and F command combinations extrude the filament and completely change the nozzle’s position, respectively.

For example, G1 X10 Y10 F500, G1 Z1, G1 X20 E10mm F100, and G1 X10 will instruct the printer to move the nozzle to a 10,10 coordinate position on the print bed, bring the nozzle closer to the print head, extrude 10 mm of filament while moving to the X position at a speed of 100 mm/min, then move back to the first position (X10).

This instruction summarily means to change position, extrude the filament, and then return to the first position so that the nozzle can be cleaned or wiped.

Benefits of Using G-Code for 3D Printing

  • Automation: G-code program execution improves the 3D printer’s efficiency by automating which and how commands are given to a working 3D printer. With G-code, the 3D printer knows its next activity without the need for human intervention throughout the entire duration of a print job. Thus, reducing manual labor, time, energy, and costs in the long run.
  • Accuracy: G-code is designed to give the most precise print results possible by ensuring that parts created with 3D printing are consistent. It can even account for small variances in measurements.
  • Cost Savings: 3D printing optimized with G-code significantly reduces the cost of labor and materials. It eliminates the manual labor costs associated with inputting the 3D model into the printer, monitoring progress, and switching off the printing machine.
  • Scalability: G-code is compatible with any project, from small to large-sized models. Scalability means users can use G-code for various projects, from basic prototyping to full-scale production runs.
  • Versatility: G-code allows 3D printers to use different materials, making prototyping or creating complex parts with various properties and textures easier. It also helps reduce trial and error with different materials since G-code provides the instructions for consistent printing.
  • Accurate Reports: G-code has made it possible for users to have an idea of how the model will look after a successful print job. The M125 command, for example, reports settings that could help users understand an automatic bed leveling command.

Overall, G-code provides a cost-effective and efficient solution for 3D printing projects of any size and complexity. G-code is essential for companies looking to maximize their 3D printing capabilities by automating tasks, ensuring accuracy, and providing versatility.

Tips for Creating Better G-Code for 3D Printing

There is no perfect G-code because the G-code command queue used for a printing job may not work well for another 3D model printing job because the required coordinate parameters may differ. However, it is possible to create better G-code for a successful job.

Below are some tips that can help you create a better G-code that is compatible with the print time for the designed 3D model.

Choose the Right Slicing Software

One of the best decisions you can make when creating G-Code for 3D printing is selecting a slicing software to work with. It’s crucial to select a program that will help you generate high-quality G-code and produce the best prints possible.

However, ensure that the slicer program is compatible with your 3D printer; this way, you can create a simple enough G-code. You can further your effort by doing some test runs to find the one that works best for you and your needs.

Understand the Basics

A good understanding of the principles of G-Code is essential when creating 3D prints.

Before 3D printing, confirm that you can understand several basic reports on its settings, such as the bed leveling system report, the temperature report (e.g., extruder temperature and bed temperature), the speed report, the layer height report, and the troubleshooting reports.

Understanding how to use these reports to permit 3D printing execution with G-code will help you get better results and avoid frustration in the future.

Use Miscellaneous commands

Although G-codes that belong to a wider range of operations are enough to create high-quality models, it is better to add miscellaneous commands, i.e., programs that majorly control the 3D printer firmware (e.g., the fan speed and chamber temperature).

Test Before Printing

It’s important to always test your G-Code before sending it off to the printer, as there could be errors with the G-code commands that you won’t be able to detect until after you start printing.

We recommend using a simulator program to run through each code line or a sensor to report the situation of the firmware setting. Doing this will help ensure everything looks correct before you set the print job timer.

Use an Adhesion Assistant

When you use adhesion assistance such as Skirt (if you are an expert) and Raft (if you have just begun your G-code journey), errors at the beginning and during the printing process will be reduced.

This is because an adhesion assistant will help your 3D print strongly attach itself to the print bed, prevent detachment during the print time, and partly enable you to detect any problems with the 3D printer, such as a problem with the printer’s current temperature.

Keep Learning

Finally, don’t be afraid to keep exploring and learning more about G-Code. There are always improved G-code programs, techniques, and processes, so staying on top of the latest developments in 3D printing technology will help you remain important in the 3D printing community.

How to Troubleshoot Problems With Your G-Code for 3D Printing

If you’re 3D printing, you probably use a lot of G-Code commands. After all, it is the language of 3D printing that tells your 3D printer machine how to move and when to stop. But what happens when something goes wrong with your G-Code command queue? How do you troubleshoot it?

The Manual Method

  • The first step in manually troubleshooting your G-Code is to identify the problem. It could be a missing file, incorrect command queues, or an issue with the slicer software. You are to open the file in a text editor and look for typos or mistakes.
  • The next step is the correction. If you spot something wrong, make the necessary corrections and re-upload the corrected G-Code command queue to your 3D printer.

The Debugger Software Method

Another way to troubleshoot errors with your G-Code is to use the G Debugger software. The 3D printing community designed it to help you easily find and fix coding mistakes.

  • First, upload your G-Code into the software, and it will show you any errors that need to be corrected.
  • Second, transfer this tested G-code command queue into a text editor or slicer software.
  • Lastly, correct your mistakes, save it, and then re-upload the corrected G-code into your 3D printer.

Troubleshooting problems with G-Code can be tricky, but with some patience and attention to detail, you should be able to get your 3D printer up and running again in no time! Remember that it’s always important to double-check your G-Code for accuracy before sending it off to the 3D printer.

4 Resources for Learning More G-Code Commands in 3D Printing

Are you looking to learn more about G-code in 3D printing? We have some insights on 4 of the best resources available! These 4 resources are a great place to start if you want to learn more about G-code in 3D printing.

Whether you’re just getting started or want to brush up on your skills, these resources will help. They include the following:

  • First up is How to Mechatronics: This is an in-depth guide that explains how to read and understand various G-code commands. It also explains how to write G-code and gives various visual examples to ensure you can do as it says.
  • Second is Simplify3D: Simplify3D provided help to users who recently started learning 3D printing program execution through G-code CNC program language. It details the 10 most important G-code commands you should use.
  • Third on the list is the CNC cookbook: This resource references important G-code commands in tabular form. It gives users a simple yet comprehensive bird’s eye view of important G-code commands such as the M-code or Haas G-code.
  • Finally, Haas: Haas published an extensive list of G-Code for Mill machines that you can use during the post-processing process of your object model.

The CNC mill machine is simply a machine that can automate the re-shaping of object models, so with the list of various Haas G-codes, you are ready to build a successful 3D printing business.

7 Different Software Used to Generate G-Code for 3D Printing

3D printing and its associated software have revolutionized how we design, prototype, manufacture, and bring designs to life. By using these 7 different software-based programs available today, you can easily generate G-Code for 3D printing. Let’s take a look at these 7 programs and their specific descriptions:


This free software for 3D printing offers great features, such as automatic slicing and the ability to export G-code files to your printer easily. It also has a large library of 3D models, so you can get started quickly with any design.


Cura is the most popular 3D printing software on the market. It offers a powerful suite of tools to help you create high-quality prints. It can generate G-code quickly and accurately, too.


With its intuitive interface, Simplify3D allows users to manipulate and preview their 3D models in real-time before generating G-code. It also supports a variety of 3D printers, making it an ideal choice for those looking to get started quickly.


This open-source software is known for its customization options and ability to generate G-code quickly and accurately while providing users with plenty of customization options. It can also virtually generate G-code for 3D printers.


This software is designed for novice and advanced users, providing plenty of customization options to guarantee that your prints come out perfectly. It can also generate G-code quickly and accurately.


Kisslicer mainly targets professionals, offering an intuitive interface and a fast G-code generation process. Users can also use it to generate copies of the same G-code for multiple prints.


Meshmixer is designed specifically for 3D printing and offers a wide range of tools that make it easy to create detailed models with complex structures and parameters. It can also generate G-code quickly and accurately.

Despite the wide range of software options available for G-code creation, creating stunning 3D models doesn’t have to come at a high cost – these tools can help you generate G-codes affordably.

Frequently Asked Questions on What Is G-Code in 3D Printing

Do All 3D Printers Use G-Code?

No. Although G-code is the most commonly used language for CNC machines (e.g., the 3D printer), the CNC program also understands other codes, such as M-codes. Besides, several slicer software programs can help you translate your code into a language that your 3D printer will understand.

What Is the Difference Between G-Code and STL?

G-code and STL file formats each have a function.
G-code, for example, controls the movement of the 3D printer with the help of the 3D printer’s firmware. STL, on the other hand, is a visual aid for the 3D printer, i.e., it represents the geometry and shape of the object model.

How Do I Create a G-Code File for My 3D Printer?

Apart from using the default settings of a 3D printer and a G-code editor such as the G-wizard editor, you can also use an efficient Slicer (e.g., Cura) to generate your G-code.

What Is G-Code With an Example?

G-code is a computer language in the form of a CNC program. Its functions by controlling the movement of the computer you insert it into. A good example of G-code is:
G2 Ennn Fnnn: Generate support structures by extruding nnn (mm) of material at nnn (mm/min).
G0 Xnnn Ynnn Znnn: Move nnn (mm) in the X direction, nnn (mm) in the Y direction, and 30 mm in the Z direction.
G1 Ennn Fnnn: Extrude nnn (mm) of material here at nnn (mm/min).

How Do I Turn My 3D Printer Into a G-Code

You can’t. Rather, you can turn your 3D printer into a G-code generating machine with the below steps.
. Create the STL file for the model object.
. Install the STL file into a Slicer software such as Cura.
. Play around with the Slicer’s G-code settings.
. Slice the object model, then transfer it to a storage device.

Final Thought

In conclusion, G-code is an essential language every 3D printer user should understand. It allows you to easily make precise and intricate 3D prints by providing instructions for the printer.

Additionally, due to its flexibility and compatibility, you can use G-code for other CNC (computer numerical control) machines, such as CNC milling and laser cutting machines. 

With its wide range of applications, G-code is an invaluable tool for those who want to take their 3D printing projects to the next level. So, if you’re looking to get into 3D printing or want to learn more about it, ensure you learn G-code here. It is the key to unlocking your 3D printing potential.

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